A general purpose cold finger using a vibration-free mounted He closed-cycle cryostata)

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Abstract
A method for mounting a He closed‐cycle cryostat which consists of an exchange gas envelope around the cold head to cool an independently supported sample mount as in model DE202 with a DMX‐20 interface from APD Cryogenics, Inc. is described. No detectable vibration of the sample mount is observed as evaluated using 57Fe Mössbauer spectroscopy and a piezoelectric accelerometer. Using a 25 μm thick α‐Fe foil a linewidth of 0.231(3) mm/s at 300 K with the refrigerator on and the same linewidth with the refrigerator off is observed. The easy optical access afforded by such a cold finger makes it an economical general purpose laboratory tool for performing low‐T spectroscopic investigations, such as microwave, optical, γ‐ray, x‐ray and neutron‐scattering measurements. Other applications include electrical transport, SIMS, RBS, and rare‐gas matrix isolation.